Process of manufacturing tetra-ethyl lead



Patented Mar. 27, 1928.

UNITED STATES PATENT OFFICE.

WILLIAM S. CALCOTT, OF PENNS GBOVE, ALFRED E. PARMELEE, OF CARNEYS POINT, AND FREDERICK R. LORRIMAN, OF PENNS GROVE, NEW JERSEY, ASSIGNORS TO E. I. DU PONT DE N EMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORA- TION OF DELAWARE.

PROCESS OF MANUFACTUBING TETRA-ETI HYL LEAD.

No Drawing.

This invention relates to the production of tetra-ethyl lead, and more particularly to the production of the same'by the interaction of lead-sodium-potassium alloy with 'chlorine.

In the manufacture of tetra-ethyl lead by the so-called chloride process, the method used in the past consists, in general, of heating together ethyl chloride and a very l0 definite alloy of sodium and leadPbNa.

The conditions of temperature and pressure have been varied widely, although it may be stated that as a rule temperatures of somewhere in the neighborhood of 45 C. in the cooling-bath water have been employcd in the laboratory. The precise method of carrying out the necessary mixing and heating have, naturally, Varied widely, but the process has, basically, always been the heating of ethyl chloride with 'PbNa.

We have discovered that a. still smoother reaction may be obtained if a different alloy is substituted for the lead-sodium alloy PbNa.

An object of the present invention is to secure greater yields of tetra-ethyl lead.

Other objects will appear as the description proceeds.

The present invention may be accomplished in the following. embodiment in which we have found that the use of the alloy Pb (Na,K) in place of PbNa starts the reaction with ethyl chloride more readily, can be carried out at a lower temperature, and gives higher yields of tetra-ethyl lead. While it might appear from their positions in the periodic table that potas- 'sium could be substituted for sodium in the alloy PbNa, it is not predictable that the substitution of a small amount of the sodium by potassium would give such a pronounced improvement in yield and ease of operating.

As an illustrationof the advantage to be gained by the use of the alloy Pb(Na,K) 'over PbNa, the following are typical results:

Temperature of cooling bath, C.

A. Alkali metal content of alloy, 9.5%

' Na+0.75% K. Average yield after 4 hrs.

composition Pb(Na,K)

Application filed November 3, 1826. Serial No. 146,083.

heating, 78.7 Average yield after 6 hrs. heating, 84.9%.

B. Alkali metal content of alloy, 10% Na.

Average yield after 4 hrs. heating, 70.9%. Average yield after '6 hrs. heating, 71.7%. With the cooling bath temperature of 30 0., the difference is still more strikin A. Alloy containing 9.4% Na+0.75% Yield after 8 hours heating, 82.5%.

B. Alloy containing 10% Na. Yield after lead which comprises treating lead, intimately associated with sodium and potassium, with ethyl chloride.

2. The process of producing tetra-ethyl lead comprising effecting a reaction in a closed vessel between ethyl chloride and an .alloy containing lead, sodium, and potassium.

3. In the process of producing tetra-ethyl lead, the step which comprises heatin together ethyl chloride and an alloy 0 the 4. In the process of producing tetra-ethyl lead, the step which comprises eifectin a reaction between ethyl chloride and an afioy of lead containing approximately 9 parts of sodium to one part of otassium.

5. In the process of producing tetra-ethyl lead comprising mixing an alloy of lead containin sodium and potassium with ethyl chloride, eating the mixture and subjecting the mixture to a cooling bath.

6. In the process of producin tetra-ethyl lead comprismg mixing an a oy of lead containin sodium and potassium with ethyl chloride, eating the mlxture and subjecting the mixture to a cooling bath of a temperature of 30 C. to 45 C.

7. In the process of producin tetra-ethyl lead comprising mixing an a 0y of lead loo containing sodiumand potassium with ethyl chloride in a closed vessel, heating the miximmersing the vessel and contents in amature and then immersing the vessel and oon- "ter bath of a temperature of 30 C to45 (1- tents in a water bath. In testimony whereof we affix our signa- 8. 'In the process of producing tetra-ethyl tures. y v

lead comprising mixing an alloy of lead, conv taining approximately 9 parts of sodium to WILLIAM S CALCOTT. 1 -1.part' of potassium, with ethyl chloride in ALFRED IL PARMELEE;

a closed vessel, heating the mixture and en FREDERICK R. 'LORRIMAN. 

